A number of techniques are available for treating cardiovascular disease such as cardiovascular bypass surgery, coronary angioplasty, laser angioplasty and atherectomy. These techniques are generally applied to bypass or open lesions in coronary vessels to restore or increase blood flow to the heart muscle. In some patient's the number of lesions is so great, or the location so remote in the patient's vasculature, that restoring adequate blood flow to the heart muscle is difficult.
TMR has been developed as an alternative to these techniques which are directed at bypassing or removing lesions. TMR is performed by boring channels directly into the myocardium of the heart. In one such procedure, a laser catheter is advanced into the left ventricle. Laser radiation is then focused on the myocardium to create a channel. It has been found that creating several channels may be useful.
TMR has been performed by forming channels with laser energy as described above. TMR has also been performed by cutting a channel with a sharpened probe or blade. The channels cut by laser have a width proportional to the width of the focused laser radiation used to make the channels. When a laser is used, tissue is vaporized to form the channel. When the procedure is performed with a blade, tissue is not removed, but merely pierced or cut.
Lasers used to performed TMR can be costly and the depth of the channels formed can be difficult to control. Cutting the myocardium with a blade does not remove material from the incision. Removing, or in the case of the TMR laser techniques, vaporization of tissue is believed to enhance the success of the TMR procedure.